With many components, in particular castings, material has to subsequently be removed, for example to form recesses or through-holes. In particular in the case of turbine components, which have film-cooling holes for cooling purposes, holes are introduced retrospectively following production of the component.
Turbine components of this type often also have layers, such as for example a metallic interlayer and/or a ceramic outer layer. The film-cooling holes then have to be produced through the layers and the substrate (casting).
U.S. Pat. No. 6,172,331 and U.S. Pat. No. 6,054,673 disclose a laser drilling method for introducing holes into layer systems in which ultrashort laser pulse lengths are used. A laser pulse length is searched for within a defined laser pulse length range and used to produce the hole.
DE 100 63 309 A1 discloses a process for producing a cooling air opening by means of a laser, in which the laser parameters are set in such a way that material is removed by sublimation.
The use of ultrashort laser pulses of this type is expensive and very time-consuming on account of their low mean powers.